For many devices, particularly catheters, it is desirable to reduce friction as the catheter for example is inserted into the body of a patient. In virtually all medical uses of that type, the catheter surface is exposed to moisture from the patient's own body fluids. Thus, injury to tissues of the patient is reduced if the catheter, with a moistened surface, can be advanced with reduced friction into its desired position within the patient. A reduction of friction results in a reduction of the necessary insertion force within the patient, plus a reduced insertion force to install the catheter within a catheter sheath introducer or the like. At the same time, it is important for the catheter to exhibit good antithrombogenic characteristics if it is to be installed in the arteriovenous system of the patient.
To accomplish this, various friction lowering coatings have been applied to catheters and other devices. See for example Micklus et al. U.S. Pat. Nos. 4,119,094; and 4,100,309. See also Balazs et al. U.S. Pat. Nos. 4,500,676; and 4,487,865; Creasy et al. U.S. Pat. No. 4,642,267; and Lorenz et al. U.S. Pat. No. 4,769,013..
In accordance with this invention, an improved hydratable, friction-reducing coating for catheters, or any other desired article, is provided, in which the friction-reducing coating is extremely effective, particularly in the presence of substantial moisture, and also very easy to apply as a coating to a base material without the need of inflammable, toxic, organic solvents to serve as a carrier as the coating is applied to a base material. Instead, a simple, primarily aqueous dispersion of the coating ingredient can be used to apply the coating in safe and simple manner, without the need for any curing step to effect cross-linking. Also, water-dispersable therapeutic agents or the like may be added to the aqueous dispersion as coating ingredients.
Additionally, the components of the friction-reducing coating of this invention may be very nontoxic, and unlikely to set off allergic or other sensitizing reactions in the patient or other user. Likewise, the coating in accordance with this invention can have very low thrombogenicity, making it an excellent candidate for use with an arteriovenous catheter.
Furthermore, the friction-reducing coating of this invention can bond well to selected base materials, depending upon the specific nature of the coating, so that catheters or other articles may exhibit greatly reduced friction under hydrated conditions without loss of the coating through wear, coupled with good acceptability from a toxicological standpoint.